This invention relates generally to a method and apparatus for shaping airfoils and more specifically to a method and apparatus for shaping the leading and/or trailing edge portions of an airfoil of the type utilized in turbines, compressors and similar fluid-flow devices.
The leading and trailing edge portions of airfoils which are utilized in gas turbine engines have previously been finished by hand grinding or other manual finishing methods. These manual finishing methods are relatively inaccurate and it is extremely difficult, if not impossible, to hold the radius of curvature of an airfoil edge to a very small tolerance. Since the operating efficiency of a turbine engine is enhanced if the leading and trailing edges are accurately finished to relatively small tolerances, more than two hours have been previously been required to hand shape the leading and trailing edge portions of a turbine blade.
In order to expedite the construction of an airfoil, known prior art patents have disclosed various types of machines and methods for shaping either or both the leading and trailing edge portions of an airfoil. Some of these known airfoil finishing apparatus and methods are disclosed in U.S. Pat. Nos. 2,681,500; 2,680,392; and 2,336,303. For example, U.S. Pat. No. 2,680,392 discloses an apparatus for swaging the edge portion of an airfoil. However, this apparatus cannot be utilized to compensate for either bow or twist in the edge portion of the airfoil. If a cutting or milling tool was utilized in place of the swaging tool of this known apparatus, the cutting tool would not follow the contour of the edge of the blade in such a manner as to provide an accurately shaped blade.